124 



BACTERIOLOGY. 



the tube e, and is provided a short distance above this 

 point with a capillary opening g, in one of its sides. 



FIG. 29. 



Mercurial thermo-regulator. 



When ready for use the cylinder e is filled with mercury 

 up to about the level shown in the figure. It is then 

 allowed to stand, or is suspended, in the bath the tem- 

 perature of which it is to regulate. The rubber tubing 

 coming from the gas supply is attached to the outer end 

 of the glass tube a, and the tube going to the burner is 

 slipped over the branch tube b. The gas is turned on and 

 the burner lighted and placed under the bath. The gas 



